The present invention relates generally to contacts which periodically make and break an electrical circuit and more particularly to such contacts for use in an internal combustion engine ignition system.
Breaker or contact points are well known in both magnetos and the conventional battery operated type ignition systems and typically include a member which follows a rotating cam to open and close the contacts thereby periodically interrupting ignition coil primary winding current flow inducing a high voltage ignition spark producing current surge in a secondary ignition coil winding.
One problem with such contact systems is that if the contacting surfaces are not kept clean, the conductivity and therefore also ignition operation, are adversely effected. It is frequently difficult to prevent contact contamination, especially since such breaker point systems are frequently located closely adjacent to and actuated by a crank or cam shaft extending from the engine crankcase, and oil leakage about that shaft tends to foul the contact surfaces. Another problem associated with such breaker point systems is that the cam follower which is typically an insulating member fastened to a movable breaker point arm and riding on the cam surface wears, requiring periodic readjustmentof point gap. Such readjustments of the point gap frequently require partial dissembly of the ignition system to gain access to the adjustable member, resulting in undesirable time and expense of maintenance. This undesirable aspect may also be present during initial assembly of the system.